Contact surfaces for connections that are particularly corrosion-resistant and provide reliable electrical conduction between electronic circuit boards and other electronic or electrical components are usually produced from tin, silver or gold. For electronic applications in motor vehicles, which are exposed to extreme environmental effects, contact arrangements which are based on spring elements and connection structures with a complex geometry are furthermore known. These spring elements and connection structures are provided with a surface finish made of tin, silver or gold and are then connected in an electrically conductive manner to the circuit board. However, the complexity of the spring elements used and of the connection structures leads to high production costs and quite often requires a larger installation space.
Electrical contact arrangements which use a metal compression spring supported on a conductor track or a contact path of a circuit board to electrically connect an external component, e.g. a solenoid valve or a sensor, are further-more known for use in motor vehicles. In such a structure, a gold-plated contact spring and a conductor track composed of copper as the base material, which is gold-plated at least in the contact zone, are employed as contact partners in such a structure, for example, the spring and the conductor track being very largely impervious to damaging corrosive climatic effects and therefore allowing reliable electrical connection. However, a barrier layer of nickel is required for cost-effective gold-plating in order to suppress diffusion processes. However, it is precisely this barrier layer which has proven sensitive to climatic effects, especially in combination with the known press-fit technology, in which electrical components are secured mechanically in circuit board holes that are metal-coated or provided with metal sleeves simply by being pressed in and, at the same time, are brought into electrical contact with the conductor tracks of the circuit board, and this sensitivity can lead to the formation of cracks, subsurface corrosion and local corrosion at the contact points.
Chemical corrosion effects and/or frictional corrosion phenomena can also occur with other pairs of materials for the contact spring and the circuit board, such as silver-silver, silver-tin or silver-tin solder, in the presence of dis-advantageous climatic effects, vibration-related relative movements between the contact spring and the circuit board and/or in the case of relatively high cur-rent loads, and the consequences of these corrosion effects or phenomena can extend to total failure of the electrical contact point concerned.
DE 102 44 760 A1 discloses a pressure sensor subassembly having an electrical connection for a measuring element. The electrical connection between the measuring elements and a plurality of contacts, which are embedded in a contact support surrounding the measuring elements, is obtained by means of a “bond” by microwelding. The external electrical connection of the pressure sensor subassembly is accomplished by means of a plurality of spring contacts embodied in the manner of helical compression springs, which are each passed through an opening in an insertion funnel which, for its part, is arranged in a pressure sensor housing. The spring contacts are supported between the contacts in the contact support and an external abutment. Within the pressure sensor housing, the spring contact is wound to form a solid block so as to be axially rigid under pressure, while, outside the pressure sensor housing, the spring contact can deflect in an axial direction. Direct electrical connection of a circuit board with the aid of the spring contacts is not envisaged.